The objective of the proposed research is to prove feasibility of a novel mitral valve (MV) coaptation mechanism introduced by coaptation plate (patent pending) to prevent ischemic mitral regurgitation based on functionality and fluid-structure interaction of the MV and coaptation plate. Ischemic mitral regurgitation results from remodeling of the ischemic left ventricle, leading to displacement of the papillary muscles, annulus dilatation and consequent tethering of the MV leaflets, which restrict the closure of the mitral leaflets. Current surgical strategies include annuloplasty, repositioning of papillary muscles, chordal and leaflet manipulation, which are all based on MV coaptation mechanism of the leaflet contact and alignment. Until now, none of them offers long term reliability. Lack of effective treatment leads to 50% mitral regurgitation recurrence in 5 years. In this proposal, the PI proposes a novel MV coaptation mechanism, a concept of MV coaptation plate, to treat ischemic mitral regurgitation. It is hypothesized that ischemic mitral regurgitation can be better treated by inserting the coaptation plate into the MV orifice and utilizing new knowledge of fluid-structure interaction in an ischemic MV with the coaptation plate. The novel concept of coaptation mechanism of the coaptation plate does not require leaflets contacting each other, but induces leaflets to contact the coaptation plate as an intermediate bridge between leaflets, and seals the leaflet gap. The 2 specific aims are: 1) evaluate efficacy of the MV coaptation plate to prevent ischemic mitral regurgitation during valve closure;2) evaluate left ventricle and MV fluid mechanics in the ischemic MV with the coaptation plate during valve opening. MV leaflet spatial configuration, gap size, pressure drop, leaflet coaptation depth and leakage during valve closure are measured and analyzed to prove efficacy of the coaptation plate. A computational fluid dynamic study on the MV, coaptation plate and left ventricle is conducted to evaluate pressure drop across the MV, shear stress, velocity, vortex pattern, and energy dissipation in the left ventricle. The novel coaptation concept of the MV introduced by the coaptation plate challenges the current MV coaptation mechanism based on leaflet contact and alignment, which depends on leaflet and annulus sizes, and chordal and papillary spatial configuration. The new coaptation mechanism of the coaptation plate requires neither touch or alignment between two MV leaflets, nor a normal or undersized annulus achieved by annuloplasty because geometry of the coaptation plate compensates leaflet displacement due to annulus dilatation and chordae tethering. Once this novel coaptation mechanism is proved to be effective and feasible, it would greatly impact current MV repair paradigms, and lead to improved surgical procedures and development of novel medical devices to prevent not only ischemic mitral regurgitation, but also mitral regurgitation of other etiologies. PUBLIC HEALTH RELEVANCE: The proposed research aims to prove feasibility of a novel mitral valve coaptation mechanism introduced by coaptation plate (patent pending) to prevent ischemic mitral regurgitation based on functionality and fluid-structure interaction of the mitral valve and coaptation plate. Once the coaptation mechanism of the coaptation plate is proved to be effective, it will greatly impact current MV repair paradigms, and lead to improved surgical procedures and development of novel medical devices to prevent mitral regurgitation with long-term reliability and decrease patient morbidity and mortality.